LM2904: LM2904P product oxidation

user6350528

Part Number: LM2904

Hi Team

We did the welding test and found that the PIN of the product did not stick tin, so the welding could not be successful.

Help to confirm whether the material has been oxidized? thank you

Best

xiaoqingTI LM2904P Solderability Test Report 20201019.pdf

over 4 years ago

0 Ron Michallick over 4 years ago

TI__Guru*** 149716 points

Hello Xiaoqing,

Can you provide a top side picture with all the symbolization clearly readable.

0 user6350528 over 4 years ago in reply to Ron Michallick

Expert 1350 points

Hi Ronald Michallick

Please see the attachment. Thanks.

0 Ron Michallick over 4 years ago in reply to user6350528

TI__Guru*** 149716 points

Xiaoqing,

This package has as roughed lead frame with a NIPDAU | SN lead finish. This finish is less shiny but it better for solderability. LM2904P is also a big package with large leads. The time window for the experiment is a wide 2 to 3 seconds. That is a big window. The missing solder is near the top where the temperature may not have been high enough to draw solder.

If a non roughened lead finish is desired then try LM2904PE4 which has a NIPDAU lead finish.

More information in this post. e2e.ti.com/.../718449

0 user6350528 over 4 years ago in reply to Ron Michallick

Expert 1350 points

Hi Ronald Michallick

The time window for the experiment is a wide 2 to 3 seconds in our test，Power ON the solder pot and preheat for 30 minutes until the temperature is stable at 245 de grees.Are we testing incorrectly?

0 Ron Michallick over 4 years ago in reply to user6350528

TI__Guru*** 149716 points

Xiaoqing,

I will consult other team members with more packaging and soldering experience to get more advice. I will reply with an update within 3 days.

0 Ron Michallick over 4 years ago in reply to Ron Michallick

TI__Guru*** 149716 points

Xiaoqing,

I have not heard anything yet. I will ping the request.

0 Ron Michallick over 4 years ago in reply to Ron Michallick

TI__Guru*** 149716 points

Xiaoqing,

JEDEC has a test procedure under J-STD-002D. It included both SnPb and Pb-free test for different type of packages. The test time is a little short. The package also need to go through a flux bath prior to solder dip. The immersion rate will also affect the test results.

Flux time should be 5 to 10 seconds and solder time should be between 4.5 and 5.5 seconds

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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LM2904: LM2904P product oxidation